1. Field of the Invention
The present invention relates generally to the field of graphics processing and more specifically to transitioning between operational modes in a hybrid graphics system.
2. Description of the Related Art
In conventional computing systems, the processing power of a central processing unit (CPU) may be supplemented using a co-processor, such as a graphics processing unit (GPU). GPUs are specialized processors that are configures to efficiently perform graphics processing operations normally performed by the CPU. GPUs may be used to offload some of the processing workload of the CPU. Conventional computing systems may also be configured with a hybrid graphics system that has multiple GPUs, including, for example, an integrated GPU (iGPU) located on the motherboard with the CPU and a discrete GPU (dGPU) located on an add-in card that is connected to the computing system via a Peripheral Component Interconnect Express (PCI Express or PCIe) expansion bus and slot.
In a hybrid graphics system, the iGPU and the dGPU operate in concert to perform graphics processing operations. The iGPU is generally sufficient for ordinary graphics processing tasks, such as web browsing, video playback, and the like. Other graphics-intensive operations, including three-dimensional (3D) rendering and video gaming, are better performed by the dGPU. The dGPU supplements the iGPU by providing the graphics processing capabilities necessary for many of these graphics-intensive applications. However, a typical dGPU generally consumes more power than a typical iGPU due to chip leakage, extra local memory, the use of an intermediary bus (such as a PCIe), dedicated voltage regulation, cooling systems, and the like. Consequently, the improved processing capability offered by a conventional hybrid graphics system is offset by higher overall power consumption compared to using an iGPU alone. However, not all user operations or applications require the use of both the iGPU and the dGPU. For example, when a user is browsing a website, the high performance processing capabilities of the dGPU are generally not required. Using conventional techniques, the dGPU continues to consume power, even when graphics-intensive operations are not required. In this situation, the hybrid graphics system consumes power unnecessarily and generates excessive heat.
In addition, the relatively high-power consumption of the dGPU is especially problematic when a hybrid graphics system is implemented on a laptop computer. As is known, the running time of the laptop computer is limited by battery life. Performing graphics processing using both an iGPU and a dGPU increases power consumption and reduces this running time when the laptop computer is operating using battery power.
Accordingly, there remains a need in the art for a more efficient technique to manage the cooperation of an iGPU and a dGPU in a hybrid graphics system.